Clinical outcome and dosimetric parameters of chemo-radiation including MRI guided adaptive brachytherapy with tandem-ovoid applicators for cervical cancer patients: a single institution experience.

Purpose: To evaluate dosimetric parameters and clinical outcome for cervical cancer patients treated with chemo-radiation and MR-image guided adaptive brachytherapy (MR-IGABT) using tandem-ovoid applicators for intracavitary or combined intracavitary/interstitial approaches.

Method: This retrospective analysis includes 46 patients treated between 2006 and 2008. Dose-volume parameters D90 HR-CTV (high-risk clinical target volume) and D(2cc) OARs (organs at risk) were determined and converted into biologically equivalent doses in 2 Gy fractions (EQD2). Clinical outcome parameters (local control (LC), progression free survival (PFS) and overall survival (OS)) were analysed actuarially and late morbidity crude rates were scored using CTCAEv3.0.

Results: Mean D90 HR-CTV was 84 (SD9) Gy EQD2 for HR-CTV volumes of mean 57 (SD37) cm(3) at time of first brachytherapy (BT). Median follow-up was 41 (range, 4-67) months. Three year LC, PFS, and OS rates were 93, 71, and 65%, respectively. Node negative patients had significantly higher 3-year survival rates compared to node positive ones (PFS 85 versus 53% (p=0.013), OS 77 versus 50% (p=0.032), respectively) with an even larger difference for patients with FIGO stages IB-IIB (PFS 87 versus 42% (p=0.002), OS 83 versus 46% (p=0.007), respectively). Late grade 3-4 mainly gastrointestinal or vaginal morbidity was observed in 4 patients (9.5%). No correlations were seen between morbidity and D(2cc) OAR values.

Conclusion: (Chemo-) radiation and MR-IGABT with tandem-ovoid applicators result in high LC and promising survival rates with reasonable morbidity.